This application relates to a coating system wherein an erosion resistant coating is secured to a housing through a fusible bond layer.
Gas turbine engines are known and, typically, include a fan delivering air into a compressor section. The compressed air is delivered into a combustion section where it is mixed with fuel and ignited. Products of this combustion pass downstream over turbine rotors driving them to rotate.
In modern gas turbine engines, providing a very efficient engine is of increasing importance. Thus, it becomes important to effectively utilize all of the energy produced in the engine. To this end, a compressor section typically includes rotating blades that are spaced from a static housing or case. Sealing surfaces are provided adjacent an outer surface of the blades to provide close clearance between the blade and the housing. This prevents leakage of the air around the blades, which would reduce the efficiency of the engine.
Gas turbine engines, for example for military applications, are being utilized more and more in environments having significant particulates, such as dust and sand. Such an environment raises challenges with regard to maintaining close clearances in the compressor section in that the sand is abrasive. Thus, the coatings provided on the case are being provided by increasingly hard coatings which are resistant to impact from abrasives such as sand. However, challenges arise in that under certain conditions the compressor blade may extend further outwardly than normal and contact this coating. Since the coating is hard, this contact can prove problematic and could result in damage to the blades.
It is also known that a bare base metal may surround the blades, which is of course also hard.